Freewheel cycle and braking mechanism therefor



July 11, 1933. v PUGH 1,917,459

FREEWHEBL CYCLE AND BRAKING MECHANISM THEREFOR Filed Nov. 3, 1950lSheets-Sheet 1 A v Z 72 6 d- E I g b 3 Q: I 1: P.

cl 0 A r g ,r g *n 1 k Fig 7 nmmnnmmmmmnm 1 fi fim J. V. PUGH FREEWHEELCYCLE AND BRAKING MECHANISM THEREFOR July 11, 1933.

Filed Nov; 3, 1930 2 Sheets-Sheet 2 Patented July. 11 1 933 UNITEDPATENT OFFIC JOHN VERNON roan, or lvinninnn, ENGLAND I I FBEEWHEEL CYCLEAnn BRAKING MECHANISM THEREFOR,

Application fil ed November 3', 1930, Serial l fe. 493,217, and in GreatBritain November 8, i929.

the hub" and also'upon a member closely 'ad-' jacent thereto and saidsprocket isadapted to move axially on toand eiiect engagementfor drivingthe hub when rotated in one dire'ction and to move axially'on to engagethe re adjacent member when oppositely rotated;

The object oi the present invention is to provide improved devices foroperating in the manner indicated.

The invention consists in a freewheel do is vice of the kind indicatedin which the chain sprocket in moving from one engagement to the otherpassesthrough a zone Where there'- is no positive rotary engagement.

The invention further consists in a free-"- 2 Wheel device as indicatedin Which the central apertureof a chain sprocket is proi' i de'd -v'vithhelically-di'sposed V-shaped intern-alteeth Wh ile complementary helically-disposed teeth upon a hub and upon a member adjacent thereto areprovided upon surfaces which taper towards one another and/or arereduced in diameter the abutting edges to provide a path on Which-thesprocket may re-' main without positively engaging either 30 member butat the same time have axially directedl force exerted thereon" bymovement of the chain.

lhe invention also consists in improve" men-ts freewheel cyclesandb'raliing' moch 5 anism therefor as indicated in the toll'ovvi ng'description.

Referring now to the accompanying draw in s igure I is a section throughthee'nd oi the hub in accordance with the invention, the upper halfshowing the helical surfaces in eleva tionand the lower half being a:-section through these parts; 7

Figure 2' is anend view of fire-adjacent: member with some of the" teethor serrationsshown thereonat the smaller and larger di al neter Figure3' man end View or the chain sp ro el'e- Figure l asectionthereehroughg:

et, and

1 Figure '5 shows the serrated part of thehub end and'the adjacentmember to a larger scalewith the chain sprocket shown in full linesindriving and dotted in intermediate positions;

Figure 6 is another View of ahnb end with a fixed or stationary adjacentmember, and

F i'gU-re 7 is a fragmental helical teeth or serrations;

Figure- 8 is another View of a hub endof a slightly modified form;

plan showing the Figure 9 is a fr'ag'inental plan similar to Figure'7; IV F gure 10 shows a longitudinalf'section through 'a'hub' in accordanceWith-the inven' mg thehelical teeth or serrations and also" thecooperating cam surfaces constituting a part of the brakmg device;

In carrying the" inventioninto effect as shown in Figures 1- to 55a'cycle'hub' a is provided at the region- Where therhain sprocket isgenerally attached thereto With a ternal teeth formed in the centralaperture of a chain sprocket b' may'en-gage. The chain sprocket 5* whichma be formed from" plate material of uni-o-rmthickness has acentralopertur'e I) provided with a ring of internal V shaped teeth orserrations b which may bedfisposed in a helical direction upon acylindrical surface a-s s'hown in Figure 4 Upon the end of the hubathereis provided v as shown in- Figures 1 and 51 an engaging I region fortheclramsprocket-Z) in the shape of a ring a of a diameter sa ffieiently larger than the central? aperture 01% the ehainsprocket to form anaxial abutment for one side thereof an'cl nexttothis ri'ng'a andretaining it upon region being situatedupon the outer side.

sMonnted upon the hub spindle 0 adjacent to the back stay'is anotherring-like member (Z with a helically-toothed region (1 which is acounterpart of the toothed portion a of the hub, this ring-like member(Z havinga screwed region adjacent the outer and larger end thereofUPOII'WlllCll a plain ring d may be screwed to form an axial abutmentforthe other side of the chain sprocket b in thesame manner as thecorresponding member a upon thehub.

The two helically-toothed and preferably conical regions a cl of the huband the adjacent memberrespectively are arranged with their smallerendsmeeting one another in the centre of a helically-screwed region uponwhich the chain sprocket Z2 is mounted and the central portion of thisregion where they two helically-toothed regions meet is adapted by asuitable reduction in diameter asshown at a and (i to provide a partialzone upon which the chain sprocket b may ride as shown in dotted linesin Figure 5 without, effecting positive engagement with eitherside or,in other words, in moving axially from the hub surface a on to theadjacent member surface (Z or from the adjacent member on tothe hub thechain sprocket passes over an intermediate region in which it is able toclatter. over or overrun both surfaces without positively engagingeither. i V r The above path or zone at, (5* will .be of a sufficientlyreduced overalldiameter to allow of the overrunning but, the points ofthe teeth 5 of the sprocket wheel will, however, be still capable ofbeing drawn by force exerted on the chain into engagement with theportions extending across the path or zone of the teeth upon the twoconical regions a, d and by this means force exerted upon the chain 111one direction or the other will cause the sprocket wheel to travelaxially either wholly on to the hub to effect driving engage menttherewith. or wholly on to the. adjacent member; I i I In Figure 6 the,hub end 6 has a ring 6 screwed thereon with helical teeth as shown inFigure 7 which may be cut by acircular .member such as a hob or thelike, theteeth being arranged to fade out into the cylindrical portionof the'ring and thus form an axial abutment for the edge of the chainsprocket b.

In this construction the adjacent member f is formed with teeth of asimilar kind to those upon the hub rin 6, the two sets of teeth beingpreferably cut at a single opera tion.

As shown in this figure the adjacent member f is clipped between thecone 9 and a washer 9 upon the hub spindle c, the washer being incontact with the chain stay 9 Figures 8 and 9' show a slightly modifiedconstruction in which the cylindrical member orhub for forming the teethis of smaller diameter and the chain sprocket Z) will move a smalleraxial distance from driving engagement with the hub h to its positionupon the adjacent member i.

In the construction; shown in Figure 10 the chain sprocket .7) isadapted tomove from one to the other of the ring j upon the hub j andthe adjacent member 7a, the teeth being of the kind described in,connection with Figures ,6 to 9. In this form, however, the adjacentmemberlc is monntedso that it, is free to rotate upon a collar 72positioned upon i the hubspindle 0 between the cone m and the chain staym. A washer or disc m is positioned upon the cone m and retains a springa in contact with the inner face of the adjacent member 7:: so that thismember is free-to rotate against the friction ofthe spring. The adjacentmember is is thus held so that on back pedaling the pedals can be movedround further than they could with an actual stationary piece. This isconvenient in a general sort of way and is also very important becauseit enables the rider to bring his pedals round to what he finds aconvenient position in traffic; presumabl with the right footer elsewiththe left foot nearestthevground. This is not only better fortrafi'ic butappears to get rid of the irritating clatter between free and driving.:The arrangement illustrated in Figure 11 shows a-larger diameterpieceio and 0 on V boththe driving hub part p and on the adaeent memberIn this arrangement a fr ctionispring a is j, provided asabove'described and the larger diameter pieces 0 and a 0 furnish asortof hump or hook on wlnch the chain wheel rests either in the drivingposition or m the free position and the chain wheel Wlll naturallyremain in its position unless some effective driveor back pedalhngeffort is applied.

The adjacent member can be used when moved to operate a. brake appliedto the cycle wheels, such an arrangement being,

shown in Figures 12 and 13 wherethe adjacent member movable as in themodi-,

iication shown in Figure 10 is provided with inclined cam surfaces 71:adapted to cooperate with complementary snrfaces 1"? formed on the rimof a disc 1" which is stopped from v rotational movement by a pin 11engaging the fork end.

The adjacent member k is providedwith an interior cone surface which isadapted to cooperate with a complementary cone surface 8' upon the hubend 8. The adjacent member when supporting the sprocket b as shown indotted lines is given a small movement by reverse movement of the pedalsand due to the engagement of its cam surfaces with the cam surfaces ofthe mem-fl her 1" is forced in an axial direction to'the left so thatthe cone surfaces k, s are brought into engagement and a braking actionexerted onthe wheel. The spring it operates to disengage the brakingsurfaces as soon as forward pedalling is resumed.

The method of forming the taperinghelicallytoothed portions and theshouldered regions adjacent thereto is given as an example of carryingthe invention into effect and these parts may be otherwise formed in anysuitable manner which will provide a non-positive engagement region orpath for the chain sprocket'when moving in an axial direction fromengagement with the hub to engagement with the adjacent member. Othermodifications and additions may also be introduced without departingfrom the nature of the invention as set forth in the foregoingstatements.

I claim:

1. A freewheel device for cycles having in combination a hub, a memberconcentric with said hub and adjacent to an end thereof, substantiallyabutting annular shoulder surfaces on said member and said hub, acentrally apertured chain sprocket adapted to ride freely on a zone atthe periphery of said abutting shoulder surfaces, internal helicallydisposed teeth formed round the aperture of said chain sprocket, twosimilar sloping surfaces of revolution one on said hub and one on saidmember receding from said shoulder surfaces and teeth thereoncomplementary to said sprocket teeth and adapted to engage fullytherewith at the remote or larger ends of said sloping surfaces.

A freewheel device for cycles having in combination a hub, a memberrotatably mounted concentric with said hub and adjacent to an endthereof, substantially abutting annular shoulder surfaces on said memherand said hub, means creating frictional resistance to the rotation ofsaid member, a centrally apertured chain sprocket adapted to ride freelyon a Zone at the periphery of said abutting shoulder surfaces, internalhelically disposed V-shaped teeth formed round the aperture of saidchain sprocket, two simila r flaring surfaces of revolution one onsaidhub and one on said member receding from said shoulder surfaces andteeth thereon complementary to said sprocket teeth and adapted to engagefullytherewith at the remote or larger ends of said flaring surfaces.

3. A freewheel device for cycles having in combination a hub, a memberconcentric with said hub and'adjacent to an end thereof, substantiallyabutting annular shoulder surfaces on said member and said'hulo, acensaid chain sprocket, two"similar surfaces of revolution one on saidhub and one on said member receding from said shoulder sur faces, teethon said similar surfaces complementary to said sprocket teeth andadapted to engage fully therewith at the remote ends of said similarsurfaces and regions on said similar surfaces between their adjacent andremote ends of such enlarged diameter that additional force is requiredto carry said sprocket over said enlarged regions from one to the otherof its extreme positions.

4. A freewheel device for cycles having in combination a hub, a memberconcentric with said hub and adjacent to an end thereof, substantiallyabutting annular shoulder surfaces on said member and said hub, acentrally apertured chain sprocket adapted to ride freely on a zone atthe periphery of said abutting shoulder surfaces, internal helicallydis- 7 posed teeth formed round the aperture of said chain sprocket, twosimilar sloping surfaces of revolution one on said hub and one on saidmember receding from said shoulder surfaces, teeth on said surfaces ofrevolution complementary to said sprocket teeth and adapted to engagefully therewith at the remote or larger ends of said sloping surfacesand collar shoulders adjacent said remote ends against which saidsprocket axially abuts due to the tooth reaction.

5. A freewheel device for cycles having in combination a hub, a memberconcentric with said hub and adjacent to an end thereof,substantiallyabutting annular shoulder surfaces on said member and saidhub, a centrally apertured chain sprocket having internal helicallydisposed teeth formed round the aperture thereof, a circular pathsurround ing said shoulder surfaces on which said sprocket rides withoutpositive rotational engagement with either the hub or the adjacentmember, said path having transverse grooves which correspond with thesprocket wheel teeth and into which grooves said teeth may be drawn bychain action to create axial movement of said sprocket, two similarsloping surfaces of revolution one on said hub and one on said memberreceding from said path and teeth thereon complementary to said sprocketteeth and adapted to enga e;

fully therewith at the remote or larger'en s of said sloping surfaces.

6. A freewheel device for cycles having in combination a hub, a memberconcentric with said hub and adjacent to an end thereof, substantiallyabutting annular shoulder surfaces on said member and saidhub, a cen}trallyapertured chain sprocket having in-- ternal helicallye disposedteeth formed round the aperture, a circular path surrounding I saidshoulder surfaces on which said sprocket rides without positiverotational engagement with either the hub or the adjacent memher, :saidpath having transverse grooves which correspond with th: sprocket wheelteeth and intoiwhich grooves said teeth may be drawn by chain action tocreate axial movement of said sprocket, two similar slop-' ing surfacesof revolution one on said hub and one on said member receding 'fIOlDsald JOHN VERNON PUGH.

